Morphological and morphometric features of the abnormal and normal saccular otoliths in flatfishes

Abstract

The fish's inner ear consists of three interconnected semicircular canals and otolith organs located in these canals, which are responsible for balance and hearing. Abnormalities in these organs can affect the vital activities of the fish. The main purpose of this study was to determine the morphological and morphometric characteristics of abnormal and normal sagittal otoliths in the four flatfish species (Lepidorhombus boscii, Platichthys flesus, Solea solea, and Pegusa lascaris) sampled from three seas (Aegean Sea, Mediterranean Sea, and Black Sea). Abnormalities in otoliths are investigated using light microscopy, scanning electron microscopy, and Raman spectroscopy. The otolith morphometric measurements and morphology are recorded for abnormal and normal otoliths for each species. It was determined that the four flatfish species examined in the present study showed differences in the morphological features of normal and abnormal otoliths in the blind and eyed sides. In addition, statistical differences were observed when the weight, length, width, perimeter, and area values of normal and abnormal otoliths of all species were compared (p < .05). The four types of saccular otoliths were defined, one normal (type 0) and three abnormal (type 1, type 2, and type 4) for four flatfish species. The current study presents for the first-time abnormal otolith morphology information on blind and eyed side sagittal otoliths in these flatfish species. Abnormalities in the anatomical structures of bony parts such as otoliths in fish may be caused by pollution, nutritional problems, stress, and environmental factors as well as a combination of these.

Otolith characterization and integrative species identification of adult mesopelagic fishes from the western North Atlantic Ocean

“…This library does not include otolith morphological descriptions; however, there are studies that focus on otolith morphometrics that can be used in conjunction with this library for more precision in identifying closely related species (Tuset et al, 2003;S ̌keljo and Ferri, 2012;Jawad et al, 2018). Additionally, abnormalities in otolith shape have been found in species, due to genetic or environmental factors (Yedier et al, 2023). In one study examining otoliths of the benthopelagic fish, Atherinella brasiliensis, four of 45 sagittal otoliths were determined to be anomalous in shape (de Carvalho Lapuch et al, 2022).…”

Differences in Otolith Microstructure between Reared and Wild Hedinichthys yarkandensis

“…A study analyzed the diferences in otolith morphology of fve Scorpaena species in diferent sea areas [9]. Research has analyzed abnormal otolith morphology information of blind eye sagittal otoliths in diferent marine Flatfsh species through otolith morphology and characteristics [10]. In addition, morphological, morphometric, and contour shape analysis methods were used to compare the sagittal otoliths of the same sea area and genus of Lepidorhombus whifagonis and Lepidorhombus boscii, and the diferences between the two were also found [11].…”